1. Technical Field
The present invention relates to a radiator for efficiently dissipating heat produced by semiconductor integrated circuits and other such electronic components, and to a method of manufacturing a radiator for raising up plate-shaped heat-radiating fins from a metal plate and integrally forming a radiator.
2. Related Art Description
Semiconductor integrated circuits and other such electronic components, which are constantly shrinking in size and increase in density, generate heat during use. Therefore, radiators for radiating heat are attached to packages for accommodating the electronic components. Forced cooling by a cooling fan can also be performed as needed.
Radiators commonly used for heat radiation in semiconductor integrated circuits and other such electronic components have a configuration wherein multiple pectinate heat-radiating fins stand straight up on a base. Bonding the radiator to the package allows the heat produced by the semiconductor integrated circuit during operation to be transmitted to the radiator and dissipated to the exterior. Such a radiator is normally manufactured by extruding or casting a metallic material with a satisfactory coefficient of thermal conductivity composed of aluminum.
One example of a radiator is disclosed in Patent Document 1 listed below. The radiator disclosed herein is provided with multiple tongue-shaped fins disposed at intervals in the longitudinal direction. Such tongue-shaped fins are formed by a method in which rectangular convexities are formed on the top surface by extrusion molding an aluminum extrusion moldable material, and the convexities are then cut out with a cutting tool.
Generally, the radiation efficiency of the radiator is substantially proportional to the surface area of the entire radiator. Therefore, multiple heat-radiating fins must be formed and the surface area increased in order to enhance the heat radiation effect of the radiator. However, since the former of the two radiator types is manufactured by extrusion molding or casting, there is a limit to how thin the heat-radiating fins can be made and how many heat-radiating fins can be formed, and it has been difficult to enhance the heat radiation effect.
Also, multiple heat-radiating fins can be formed in the method of manufacturing the latter radiator type disclosed in Patent Document 1, but the plate thickness of the base portion of the extrusion moldable material increases because the rectangular convexities formed on the top surface of the extrusion moldable material are cut out with a cutting tool. Therefore, the radiation efficiency is low because the heat from the heating element provided to the back surface of the radiator sometimes does not reach the tongue-shaped fins, and the radiating effects of the tongue-shaped fins cannot be achieved. Also, copper has a higher coefficient of thermal conductivity than aluminum, and although fashioning radiators from a copper material is inherently desirable, the problem with copper is that it cannot be extrusion-molded as shown in Patent Document 1. Therefore, the problem is that aluminum, which has a poor coefficient of thermal conductivity, must be used when extrusion molding is employed.
Because of such reasons, when tongue-shaped fins are formed by the method disclosed in Patent Document 1, the corners on both sides at the distal end of the tongue-shaped fins are formed into roughly 90-degree angles, and edges are formed in these corners, for which reason there is a danger that injury will be sustained by contact with the hands and other body parts of workers during manufacture, transport, or assembly into electronic device. There is also a danger of damage to components that come into contact with the corners of the tongue-shaped fins when radiators come into contact with each other, or with electronic devices or the like.    [Patent Document 1] JP-A 2001-102782